Use of isoxazoline compounds for treating demodicosis

ABSTRACT

The present invention relates to methods of treating demodicosis by administering an isoxazoline compound of formula (I)

FIELD OF INVENTION

The present invention relates to the prevention or treatment ofparasitic arthropod infestations of animals.

BACKGROUND OF INVENTION

Demodex spp. mites are normal commensals of the skin of a number ofanimals parasitising within the sebaceous glands connected to the hairfollicles. Should their numbers increase dramatically, they are capableof producing a disease known as demodicosis or demodectic mange.

Demodicosis is a non contagious inflammatory parasitic dermatosis causedby overpopulation of the follicular Demodex mites. Demodicosis can beclassified as localized or generalized according to the extent of thelesions. Localized demodicosis is a benign disease and most casesresolve spontaneously within six to eight weeks.

Generalized demodicosis is a severe disease with generalized lesionsthat are usually aggravated by secondary bacterial infections(pyodemodicosis). Accompanying pododermatitis is common. Dogs can havesystemic illness with generalized lymphadenopathy, lethargy, and feverwhen deep pyoderma, furunculosis, or cellulitis is seen. Diagnosis isnot difficult, as deep skin scrapings or hair plucking reveal mites,eggs, and larval forms in high numbers.

Chronic generalized demodicosis is a frustrating and difficult skindisease to treat. In dogs that are otherwise healthy, the generalizedform of the disease is unlikely to resolve without therapy.

Therapeutic options that are currently available include amitraz,ivermectin, milbemycin oxime, moxidectin orally and moxidectintopically, mostly to be given at multiple occasions (daily, weekly ormonthly) for periods of three months or more.

To be effective, these treatment regimens require high owner complianceover an extended period of time. Owner compliance can be an importantfactor in treatment success when multiple doses of a treatment spreadover a long period of time are required in order to achieve asatisfactory outcome.

A problem frequently encountered with the treatment of demodicosis indogs is the inability to ensure that a dog is absolutely free from mitesafter treatment and re-infestation can be detected months aftercompletion of a treatment that was initially considered to besuccessful.

Therefore it is desirable to provide a method to treat Demodex spp.infestation and demodicosis in animals, especially dogs, thateffectively controls mites and is convenient to administer and thereforesupports owner compliance and prevents re-infestation and relapse of thedisease.

SUMMARY OF THE INVENTION

The current invention provides to use an isoxazoline compound of formula(I)

wherein

R¹=halogen, CF₃, OCF₃, CN,

n=integer from 0 to 3, preferably 1, 2 or 3,

R²=C₁-C₃-haloalkyl, preferably CF₃ or CF₂Cl,

T=5- or 6-membered ring, which is optionally substituted by one or moreradicals Y,

Y=methyl, halomethyl, halogen, CN, NO₂, NH₂—C═S, or two adjacentradicals Y form together a chain, especially a three or four memberedchain;

Q=X—NR³R⁴ or a 5-membered N-heteroaryl ring, which is optionallysubstituted by one or more radicals;

X=CH₂, CH(CH₃), CH(CN), CO, CS,

R³=hydrogen, methyl, haloethyl, halopropyl, halobutyl, methoxymethyl,methoxyethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl,propoxymethyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl,dimethoxyethyl, propynylaminocarbonylmethyl, N-phenyl-N-methyl-amino,haloethylaminocarbonylmethyl, haloethylaminocarbonylethyl,tetrahydrofuryl, methylaminocarbonylmethyl,(N,N-dimethylamino)-carbonylmethyl, propylaminocarbonylmethyl,cyclopropylaminocarbonylmethyl, propenylaminocarbonylmethyl,haloethylaminocarbonylcyclopropyl,

wherein Z^(A)=hydrogen, halogen, cyano, halomethyl (CF₃);

R⁴=hydrogen, ethyl, methoxymethyl, ha lomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, methylcarbonyl, ethylcarbonyl,propylcarbonyl, cyclopropylcarbonyl, methoxycarbonyl,methoxymethylcarbonyl, aminocarbonyl, ethylaminocarbonylmethyl,ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl,haloethylaminocarbonylmethyl, cyanomethylaminocarbonylmethyl, orhaloethylaminocarbonylethyl;

Or R³ and R⁴ together form a substituent selected from the groupconsisting of:

or a salt or solvate or N-oxide thereof for the manufacture of amedicament for the treatment of demodicosis in mammals, especiallycompanion animals, especially dogs.

This invention also is directed to the isoxazoline compound as describedin this application or a pharmaceutical composition comprising suchisoxazoline compound for use in the treatment of generalized demodicosisin animals comprising an effective amount of an isoxazoline compound asdescribed in this specification, and, in case of the pharmaceuticalformulation, a pharmaceutically acceptable carrier.

The current invention further provides a method of controlling Demodexspp. mites in dogs comprising a single administration of an isoxazolinecompound as described in this specification.

DETAILED DESCRIPTION OF THE INVENTION

The inventors of the current invention discovered that demodicosis ofmammals can be treated by administering an effective amount of anisoxazoline compound as described in this application. It has been foundthat a single administration of such an isoxazoline compound resulted ina complete miticidal effect against Demodex spp. mites and a highefficacy against generalized demodicosis in dogs.

As it has been shown in the example, after single administration offluralaner as Bravecto® chewable tablets to dogs, mite numbers in skinscrapings were reduced by 99.8% on Day 28 and by 100% on Days 56 and 84after administration. Statistically significantly (P 0.05) fewer miteswere found on Days 56 and 84 on the Bravecto® treated dogs compared tothe dogs that received the prior art Advocate® (imidacloprid/moxidectin)treatment on three occasions in 28 day intervals.

The prior art methods for the control of generalized demodicosis requireall multiple treatments (daily or very frequent administration) ofeither amitraz or macrocyclic lactones such as milbemycin oxime,moxidection, ivermectin, doramectin or selamectin over a long timeperiod.

Such multiple treatments are very burdensome as frequent handling isnecessary, that require cooperation of the treated animal, which is notalways the case.

A further downside of the prior art methods and reason of limited ownercompliance is the high cost associated with such treatment regimens.

The prior art administration of the compounds additionally bear a highrisk of side effects of such treatments because relatively high dosagesof the miticidal compounds over an extended time period resulted in somecases in severe toxic side effects in treated animals, especially forivermectin sensitive breeds of dogs such as e.g. collies.

Especially the prior art bath treatment with amitraz additionallyrequired the owner to take special measures to avoid contact with thecompound and bathing should be done in a well-ventilated area.Furthermore clipping of the dog's hair coat was required for fullefficacy.

However I, in case the necessary treatment schedule is not completed,because of lack of owner compliance, the risk of a relapse of thedemodicosis is very high. Another reason for treatment failure is thatthe used compounds had limited efficacy and some Demodex mites survivedthe treatment.

The current inventors surprisingly found that such disadvantages of theprior art can be prevented, if an isoxazoline compound as described inthis application, especially fluralaner is used.

By the method of the current invention, that requires administration ofan effective dosage of an isoxazoline compound according to the currentinvention, a premature treatment cessation by owners will be avoided.

The isoxazoline compound for use in the current invention can bedescribed by Formula (I):

wherein

R¹=halogen, CF₃, OCF₃, CN,

n=integer from 0 to 3, preferably 1, 2 or 3,

R²=C₁-C₃-haloalkyl, preferably CF₃ or CF₂Cl,

T=5- or 6-membered ring, which is optionally substituted by one or moreradicals Y,

Y=methyl, halomethyl, halogen, CN, NO₂, NH₂—C═S, or two adjacentradicals Y form together a chain CH—CH═CH—CH, N—CH═CH—CH, CH—N═CH—CH,CH—CH═N—CH, or CH—CH═CH—N, HC═HC—CH, CH—CH═CH, CH═CH—N, N—CH═CH;

Q=X-NR³R⁴ or a 5-membered N-heteroaryl ring, which is optionallysubstituted by one or more radicals Z^(A), Z^(B) Z^(D);

X=CH₂, CH(CH₃), CH(CN), CO, CS,

R³=hydrogen, methyl, haloethyl, halopropyl, halobutyl, methoxymethyl,methoxyethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl,propoxymethyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl,dimethoxyethyl, propynylaminocarbonylmethyl, N-phenyl-N-methyl-amino,haloethylaminocarbonylmethyl, haloethylaminocarbonylethyl,tetrahydrofuryl, methylaminocarbonylmethyl,(N,N-dimethylamino)-carbonylmethyl, propylaminocarbonylmethyl,cyclopropylaminocarbonylmethyl, propenylaminocarbonylmethyl,haloethylaminocarbonylcyclopropyl,

R⁴=hydrogen, ethyl, methoxymethyl, ha lomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, methylcarbonyl, ethylcarbonyl,propylcarbonyl, cyclopropylcarbonyl, methoxycarbonyl,methoxymethylcarbonyl, aminocarbonyl, ethylaminocarbonylmethyl,ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl,haloethylaminocarbonylmethyl, cyanomethylaminocarbonylmethyl, orhaloethylaminocarbonylethyl;

or

R³ and R⁴ together form a substituent selected from the group consistingof:

wherein Z^(A)=hydrogen, halogen, cyano, halomethyl (CF₃).

In one preferred embodiment in Formula (I) T is selected from

wherein in T-1, T-3 and T-4 the radical Y is hydrogen, halogen, methyl,halomethyl, ethyl, haloethyl.

In an preferred embodiment in Formula (I) Q is selected from

wherein R³, R⁴, X and Z^(A) are as defined above.

Preferred isoxazoline compounds of Formula (I) for use in the currentinvention are:

(R¹)_(n) R² R³ R⁴ T Y Q Z X 3-Cl, 5Cl CF₃ CH₂CF₃ H T-2 — Q-1 — C(O)3-Cl, 5Cl CF₃ CH₂CH₃ H T-2 — Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂CH₂OCH₃ H T-2 —Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-2 — Q-1 — C(O) 3-Cl, 5ClCF₃ CH₂C(O)NHCH₂CH₃ H T-2 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃H T-2 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CH₃ H T-2 — Q-1 — C(O)3-CF₃, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-2 — Q-1 — C(O) 3-CF₃, 5-Cl CF₃CH₂C(O)NHCH₂CH₃ H T-2 — Q-1 — C(O) 3-Cl, 5Cl CF₃ — T-2 — Q-6 Z^(B)-73-Cl, 5Cl CF₃ — — T-2 — Q-7 Z^(B)-7 3-Cl, 5Cl CF₃ — — T-2 — Q-5 Z^(B)-73-Cl, 5Cl CF₃ — — T-2 — Q-2 Z^(D)-1 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-3CH₃ Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CC H T-3 CH₃ Q-1 — C(O) 3-Cl,5Cl CF₃ CH₂C(O)NHCH₂CN H T-3 CH₃ Q-1 — C(O) 3-Cl, 5Cl CF₃CH₂C(O)NHCH₂CH₃ H T-3 CH₃ Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ HT-3 CH₃ Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CH₃ H T-3 CH₃ Q-1 — C(O)3-Cl, 4-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 — C(O) 3-Cl, 4-Cl,5-Cl CF₃ CH₂C(O)NHCH₂CH₃ H T-3 CH₃ Q-1 — C(O) 3-Cl, 4-F, 5-Cl CF₃CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 — C(O) 3-Cl, 4-F, 5-Cl CF₃ CH₂C(O)NHCH₂CH₃H T-3 CH₃ Q-1 — C(O) 3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-20 — Q-1 — C(O)3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CH₃ H T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃CH₂C(O)NHCH₂CF₃ CH₃ T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CH₃CH₃ T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ H T-20 — Q-1 —C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CH₃ H T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃CF₃ CH₂C(O)NHCH₂CF₃ H T-21 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CH₃H T-21 — Q-1 — C(O) 3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-21 — Q-1 — C(O)3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CH₃ H T-21 — Q-1 — C(O) 3-Cl, 5-Cl CF₃CH₂CH₂SCH₃ H T-21 — Q-1 — C(O) 3-Cl, 4-Cl, 5-Cl CF₃ C(O)CH₃ H T-22 F Q-1— CH₂ 3-Cl, 4-Cl, 5-Cl CF₃ C(O)CH(CH₃)₂ H T-22 F Q-1 — CH₂ 3-Cl, 4-Cl,5-Cl CF₃ C(O)-cyclo-propyl H T-22 F Q-1 — CH₂ 3-Cl, 4-F, 5-Cl CF₃C(O)CH₃ H T-22 F Q-1 — CH₂ 3-Cl, 4-Cl, 5-Cl CF₃ C(O)CH₂CH₃ H T-22 F Q-1— CH₂ 3-Cl, 4-F, 5-Cl CF₃ C(O)CH₃ H T-22 Cl Q-1 — CH₂ 3-Cl, 5-Cl CF₃CH₂C(O)NHCH₂CF₃ H T-1 CH₃ Q-1 — C(O) 3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CH₃ HT-1 CH₃ Q-1 — C(O) 3-Cl, 5-Cl CF₃ R³-1 (Z) H T-1 CH₃ Q-1 — C(O) 3-Cl,5-Cl CF₃ R³-1 (E) H T-1 CH₃ Q-1 — C(O)

Especially preferred isoxazoline compounds for use in the currentinvention are

(R¹)_(n) R² R³ R⁴ T Y Q Z X 3-Cl, 5Cl CF₃ CH₂CF₃ H T-2 — Q-1 — C(O)3-Cl, 5Cl CF₃ CH₂CH₃ H T-2 — Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂CH₂OCH₃ H T-2 —Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-2 — Q-1 — C(O) 3-CF₃, 5-CF₃CF₃ CH₂C(O)NHCH₂CF₃ H T-2 — Q-1 — C(O) 3-CF₃, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ HT-2 — Q-1 — C(O) 3-Cl, 5Cl CF₃ — T-2 — Q-6 Z^(B)-7 3-Cl, 5Cl CF₃ — — T-2— Q-7 Z^(B)-7 3-Cl, 5Cl CF₃ — — T-2 — Q-5 Z^(B)-7 3-Cl, 5Cl CF₃ — — T-2— Q-2 Z^(D)-1 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 — C(O) 3-Cl,5Cl CF₃ CH₂C(O)NHCH₂CC H T-3 CH₃ Q-1 — C(O) 3-Cl, 5Cl CF₃ CH₂C(O)NHCH₂CNH T-3 CH₃ Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 —C(O) 3-Cl, 4-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 — C(O) 3-Cl,4-F, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃ H T-3 CH₃ Q-1 — C(O) 3-Cl, 5-Cl CF₃CH₂C(O)NHCH₂CF₃ H T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ CH₃T-20 — Q-1 — C(O) 3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ H T-20 — Q-1 — C(O)3-CF₃, 5-CF₃ CF₃ CH₂C(O)NHCH₂CF₃ H T-21 — Q-1 — C(O) 3-Cl, 5-Cl CF₃CH₂C(O)NHCH₂CF₃ H T-21 — Q-1 — C(O) 3-Cl, 5-Cl CF₃ CH₂CH₂SCH₃ H T-21 —Q-1 — C(O) 3-Cl, 4-Cl, 5-Cl CF₃ C(O)CH₃ H T-22 F Q-1 — CH₂ 3-Cl, 4-Cl,5-Cl CF₃ C(O)CH(CH₃)₂ H T-22 F Q-1 — CH₂ 3-Cl, 4-Cl, 5-Cl CF₃C(O)-cyclo-propyl H T-22 F Q-1 — CH₂ 3-Cl, 4-F, 5-Cl CF₃ C(O)CH₃ H T-22F Q-1 — CH₂ 3-Cl, 4-Cl, 5-Cl CF₃ C(O)CH₂CH₃ H T-22 F Q-1 — CH₂ 3-Cl,4-F, 5-Cl CF₃ C(O)CH₃ H T-22 Cl Q-1 — CH₂ 3-Cl, 5-Cl CF₃ CH₂C(O)NHCH₂CF₃H T-1 CH₃ Q-1 — C(O) 3-Cl, 5-Cl CF₃ R³ (Z) H T-1 CH₃ Q-1 — C(O) 3-Cl,5-Cl CF₃ R³ (E) H T-1 CH₃ Q-1 — C(O)

A more preferred isoxazoline compound for use in the current inventionhas the Formula (II),

wherein

R^(1a), R^(1b), R^(1c) are independently from each other hydrogen, Cl orCF₃, preferably R^(1a) and R^(1c) are Cl or CF₃ and R^(1b) is hydrogen,

T is

wherein

Y is methyl, bromine, Cl, F, CN or C(S)NH₂, and

Q is as described above.

In another preferred embodiment in Formula (II) R³ is H and R⁴ is—CH₂—C(O)—NH—CH₂—CF₃, —CH₂—C(O)—NH—CH₂—CH₃, —CH₂—CH₂—CF₃ or —CH₂—CF₃.

In a preferred embodiment the isoxazoline compound is4-[5-(3,5-Dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-methyl-N-[(2,2,2-trifluoro-ethylcarbamoyl)-methyl]-benzamide(CAS RN 864731-61-3-USAN fluralaner).

In another embodiment the isoxazoline compound is(Z)-4-[5-(3,5-Dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-N-[(methoxyimino)methyl]-2-methylbenzamide(CAS RN 928789-76-8).

In another embodiment the isoxazoline compound is4-[5-(3,5-dichlorophenyl)-5-(trifluoromethyl)-4H-isoxazol-3-yl]-2-methyl-N-(thietan-3-yl)benzamide(CAS RN 1164267-94-0) that was disclosed in WO2009/0080250.

In another embodiment the isoxazoline compound is Ethanone,1-[5′-[(55)-5-(3,5-dichloro-4-fluorophenyl)-4,5-dihydro-5-(trifluoromethyl)-3-isoxazolyl]spiro[azetidine-3,1′(3′H)-isobenzofuran]-1-yl]-2-(methylsulfonyl)-(Sarolaner)(CAS RN-1398609-39-6).

In another embodiment the isoxazoline compound is2-Thiophenecarboxamide,5-((55)-4,5-dihydro-5-(3,4,5-trichlorophenyl)-5-(trifluoromethyl)-3-isoxazolyl)-3-methyl-N-(2-oxo-2-((2,2,2-trifluoroethyl)amino)ethyl)-(INNLotilaner) (CAS RN-1369852-71-0).

In another preferred embodiment the isoxazoline compound is4-[5-[3-Chloro-5-(trifluoromethyl)phenyl]-4,5-dihydro-5-(trifluoromethyl)-3-isoxazolyl]-N-[2-oxo-2-[(2,2,2-trifluoroethyl)amino]ethyl]-1-naphthalenecarboxamide(CAS RN 1093861-60-9, USAN-afoxolaner) that was disclosed inWO2007/079162-.

In another embodiment the isoxazoline compound is5-[5-(3,5-Dichlorophenyl)-4,5-dihydro-5-(trifluoromethyl)-3-isoxazolyl]-3-methyl-N-[2-oxo-2-[(2,2,2-trifluoroethyl)amino]ethyl]-2-thiophenecarboxamide(CAS RN 1231754-09-8) that was disclosed in WO2010/070068.

Isoxazoline compounds and their use as antiparasitics are e.g. describedin US patent application US 2007/0066617, and International Patentapplications WO 2005/085216, WO 2007/079162, WO 2009/002809, WO2009/024541, WO 2009/003075, WO 2010/070068 and WO 2010/079077.

The method (or use) of this invention comprises to use racemic mixtures,for example, equal amounts of the enantiomers of such isoxazolinecompounds as described above. In addition, the method of this inventionincludes isoxazoline compounds that are enriched compared to the racemicmixture in an enantiomer of Formula 1. Also included are the essentiallypure enantiomers of such isoxazoline compounds.

When enantiomerically enriched, one enantiomer is present in greateramounts than the other, and the extent of enrichment can be defined byan expression of enantiomeric excess (“ee”), which is defined as(2x−I)−100%, where x is the mole fraction of the dominant enantiomer inthe mixture (e.g., an ee of 20% corresponds to a 60:40 ratio ofenantiomers). Preferably the compositions for use in the currentinvention have at least a 50% enantiomeric excess; more preferably atleast a 75% enantiomeric excess; still more preferably at least a 90%enantiomeric excess; and the most preferably at least a 94% enantiomericexcess of the more active isomer. Of particular note areenantiomerically pure embodiments of the more active isomer.

Isoxazoline compounds as described above can comprise additional chiralcenters. The method of this invention comprises racemic mixtures as wellas enriched and essentially pure stereo configurations at theseadditional chiral centers.

The reference to isoxazoline compound in this specification includesenantiomers, salts and solvates as well as N-oxides thereof that can beproduced by conventional methods.

By “treating” or “treat” or “treatment” is intended the application oradministration of a compound or composition to an animal that has aparasitic infestation for the eradication of the parasite or thereduction of the number of parasites, infesting the animal (eliminateexisting parasites). The effect can be e.g. ovicidal, larvicidalnymphicidal, or adulticidal or a combination thereof. The effect canmanifest itself directly, i.e. killing the parasites either immediatelyor after some time has elapsed, for example when molting occurs, or bydestroying their eggs, or indirectly, e.g. reducing the number of eggslaid and/or the hatching rate.

An “effective amount,” is the amount or quantity of an isoxazolinecompound as described above that is required to treat Demodex spp.infestations of animals, i.e. to alleviate or reduce parasite numbers onan animal, and/or to inhibit the development of parasite infections onan animal, in whole or in part.

This amount is readily determined by observation or detection of theparasite numbers on the animal both before and after administering anisoxazoline compound as described above to such animals, e.g. theparasite count is reduced, after a first administration, by 5% to about100%, preferably more than 50%, more than 70%, more than 90%, more than95%, more than 99%, especially 100%.

Preferably the effective amount results in microscopical cure, i.e. thatno Demodex spp. mites are present in the deep skin scrapings of affectedskin (preferably three to five scrapings of most severely affectedareas), preferably taken at several time points.

The effective amount for treatment of generalized demodicosisadditionally leads to diminishing or resolution of clinical signs ofdemodicosis as described in this application.

Typically effective (dosage) amount of isoxazoline compounds, arebetween 1 mg/kg bodyweight of the treated animal and 50 mg/kgbodyweight, or 5 mg/kg bodyweight to 45 mg/kg bw, or 10 mg/kg bw to 40mg/kg bw, or 20 to 30 mg/kg bw. In one embodiment the effective dosageis 25 mg/kg bodyweight.

In one embodiment a single dose of an effective amount of theisoxazoline compound is administered to a mammal, especially dog, thatis infested with Demodex spp. mites.

In one embodiment a single dose of an effective amount of theisoxazoline compound is administered to a dog that has been diagnosedwith a generalized canine demodicosis.

In another embodiment two doses of an effective amount of theisoxazoline compound are administered to a mammal, especially dog, thatis infested with Demodex spp. mites.

In one embodiment a two doses of an effective amount of the isoxazolinecompound are administered to a dog that has been diagnosed with ageneralized canine demodicosis.

In another embodiment three doses of an effective amount of theisoxazoline compound are administered to a mammal, especially dog, thatis infested with Demodex spp. mites.

In one embodiment a three doses of an effective amount of theisoxazoline compound are administered to a dog that has been diagnosedwith a generalized canine demodicosis.

Preferred is the systemic administration of the isoxazoline compounds.“Systemic administration” is an administration at a site remote from asite wherein at least a portion of the target parasites reside. Withsystemic administration, at least a portion of the isoxazoline compoundreaches the target parasite via the animal recipient's bloodstream,other body fluids (lymph fluids), and/or tissues (e.g., skin or fattissue). This is in contrast to “contact activity” were the surface ofthe parasite body is directly exposed to the isoxazoline compound.Typically, the parasite ingests the systemic administered isoxazolinealong with the animal recipient's blood, other body fluids, and/ortissue. Systemic administration may be achieved in several forms, e.g.oral, parenteral or via topical administration wherein the isoxazolinecompound is transdermally absorbed.

In some embodiments, the isoxazoline compound is systemicallyadministered via an oral route in a unit dosage form, such as, forexample, a soft or hard capsule, a pill, a powder, granules, a tablet(e.g., a chewable tablet), a paste, a solution, a suspension (aqueous ornon-aqueous), an emulsion (oil-in-water or water-in-oil), an elixir, asyrup, a bolus, a drench, or via the animal recipient's feed or drinkingwater. Alternatively oral administration can be performed via the animalrecipient's feed or drinking water e.g. it may be intimately dispersedin the animal recipient's regular feed, used as a top dressing, or inthe form of pellets or liquid that is added to the finished feed.

One form of oral administration is a dosage form, e.g. a chewablecomposition, such as a chewable tablet. Examples of chewable tabletscomprising isoxazoline compounds of formula (I) were described inWO2013/150052 and WO2013/150055. The composition of the chewable tabletsthat is disclosed in the examples of these documents is incorporated byreference. Alternative chewable tablets are described in WO2013/119442.

Oral veterinary compositions in the form of a “chewable tablet”,sometimes referred to as “soft chewable compositions” or “soft chew”,are usually convenient to administer to certain animals, particularlycats and dogs, preferably dogs, and may be used effectively to doseveterinary medicine to these animals.

A “Chewable tablet”, “Soft chew” or “Soft chewable pharmaceuticalproduct” is intended to mean a pharmaceutical unit dose that is solid atroom temperature and that is after oral administration soft to chew bythe animal and which is functionally chewy because the product has someplastic texture during the process of mastication in the mouth. Suchsoft chews have a softness that is similar to a cooked ground meatpetty. The chewable tablet or soft chew comprises a carrier and othernon-active ingredients.

The isoxazoline compound alternatively (or additionally) may besystemically administered topically using a transdermal formulation(i.e., a formulation that passes through the skin). Alternatively (oradditionally), the composition may be systemically administeredtopically via the mucosa. The isoxazoline composition alternatively (oradditionally) may be systemically administered parenterally, such as viaintramuscular injection, intravenous injection, subcutaneous injection,implant (e.g., subcutaneous implant), infusion, bolus, etc.

The animals may receive an isoxazoline compound as defined earlier once,two times or three times until the Demodex mite infestation iscontrolled and the generalized demodicosis is successfully treated. Onetreatment provides effectiveness against Demodex spp. mites for at least4 weeks, 8 weeks, 12 weeks, 16 weeks or 20 weeks, or 24 weeks.

In general the isoxazoline compound can be administered to all speciesof animals that have Demodex spp. infestation or require treatment of ademodicosis.

The recipient of the product may be a livestock animal, e.g. sheep,cattle, pig, goat; or a companion animal, e.g. dog, cat, or horse.Especially preferred is the use in companion animals, e.g. dogs or cats,especially dogs.

Demodex spp. mites that can be controlled by the use according to thecurrent invention are e.g. Demodex canis, Demodex injai, Demodex cornei,Demodex. cati, Demodex gatoi, Demodex bovis, Demodex ovis, Demodexcaprae, Demodex aries.

A “Demodex mite infestation” refers to the presence of parasites innumbers that pose a risk of r harm to animals.

By using the isoxazoline compounds as described in this applicationdisadvantages of the prior art can be avoided, because a single (ormaximal two or three times, depending on the isoxazoline compound used)administration of the compound would be necessary to achieve the desiredeffect.

Demodicosis is diagnosed by clinical evaluation and deep skin scrapingsthat is analysed using a microscope for mites present. Demodicosis isconsidered generalized when five or more areas of localized disease areobserved, or pododemodicosis is observed on two or more feet, or when anentire body region is involved. Demodicosis can also be categorized aseither juvenile (dogs up to 18 months of age), adult onset (dogsgenerally older than four years of age with no previous history ofdisease), or chronic generalized (persisting disease for at least sixmonths).

Depending on the specific isoxazoline compound used, the administrationallows to completely inhibit or kill the Demodex spp. mites present onthe animal that cause the demodicosis. Preferably, microscopic cure,i.e. multiple skin scrapings without any Demodex mites (eggs, larvae,nymphs and adults) is obtained by the administration of the isoxazolinecompound. Preferably only one administration is necessary formicroscopic cure.

The administration of the isoxazoline compound, e.g. fluralaner is ableto reduce the clinical signs of the demodicosis, and preferably at leastone of the dermatological signs, e.g. the skin lesions, such aserythema, casts, pustules, scales and crusts, exudation, ulceration andhair loss up to alopecia is reduced significantly compared to thesituation before treatment or without treatment.

The administration of the isoxazoline compound, e.g. fluralaner is ableto cure together with a symptomatic therapy (e.g. antibiotics orantiseptics) the appearance of systemic symptoms such as generalizedlymphadenopathy, lethargy, and fever.

The treatment of canine generalized demodicosis in most cases requiresadjunctive therapy. In addition to the effective miticidal therapy bythe isoxazoline compounds according to the current invention, treatmentof concurrent bacterial skin infection, internal parasites and existingunderlying systemic diseases might be undertaken for successfultreatment.

The isoxazoline compound as described in this application can be usedconcurrently with suitable antibiotics in order to control the secondarybacterial skin infection pyoderma that is usually associated withgeneralized demodicosis. Superficial pyoderma can be treated with oralantibiotics or topical antibiotics. In certain cases topical treatmentwith benzoyl peroxide or chlorhexidine—based shampoos will be useful tocontrol the bacterial secondary infections.

Example

Efficacy of orally administered fluralaner (as Bravecto® chewabletablets 13.64% fluralaner) compared to topically applied Advocate® (10-%imidacloprid/2.5% moxidectin) against generalized demodicosis in dogs.

Methods

Study Set-Up

The study was designed as a parallel group, blinded, randomized, singlecentre, and positive controlled efficacy study. Bravecto® administeredas chewable tablets on a single occasion was the test product andAdvocate®, administered three times at 28 day intervals (according tothe product label) was included as a positive control.

The test system was the individual dog. Dogs with clinical signs ofgeneralized demodicosis, e.g. erythema, hair loss, comedones, follicularcasts and crusts were enrolled, with consent from their owners, in thestudy and were returned to their owners on completion of the animalphase.

Dogs included in the study were mostly mongrels and of both sexes, olderthan 12 months, weighed between 3.5 and 13.7 kg, and except for clinicalsigns of generalized demodicosis, the dogs were healthy and as far ascould be determined the dogs had not been treated with a glucocorticoidor any product with a miticidal effect for at least 12 weeks prior toinclusion. Additional requirements for inclusion were that deep skinscrapings performed before treatment had to be positive for Demodex spp.mites.

Sixteen dogs (7 male and 9 female), ranked within sex in descendingorder of individual pre-treatment mite counts were included in the studyand allocated to two equal groups. Each dog was housed individually forthe duration of the study in an indoor/outdoor run, without contactbetween animals, and was fed once a day according to the foodmanufacturer's recommendations. Potable municipal water was available adlibitum.

Each dog was acclimatized to the housing and maintenance conditions forat least 14 days before treatment. As a precautionary measure all dogswere treated subcutaneously with an antibiotic (cefovecin), appropriatefor the treatment of pyoderma on Days −14, −1, 13 and 27. Additionally,on Days −14 and 27, deep skin biopsies were taken from each dog aftersedation. The biopsies indicated that exudative pyoderma was present intwo dogs in each group on Day −14 and that it had cleared by Day 27.Chronic dermatitis, epidermal acanthosis and hyperkeratosis was presentand unchanged in all dogs on both occasions. No inflammatory cells orbacteria were observed in the Day 27 biopsies and antimicrobial therapywas discontinued. Twice during acclimatization (Day −14 and Day −1) andon Days 27/28, 56 and 84 after treatment each dog was clinicallyexamined by a veterinarian.

The dogs were weighed on a calibrated and verified electronic scale onDays −2, 13, 27, 41, 55, 69 and 84 for dose calculation for treatment,for the use of sedatives for skin scrapings and to document the bodyweight during the study period. General health observations wereperformed daily throughout the complete study period.

Treatment

On Day 0, dogs of one group were treated once orally with Bravecto®chewable tablets, based on the dog's individual body weight, to achievea minimum dose of 25 mg/kg body weight and an efficacy over 12 weeksfollowing treatment. The chewable tablet(s) were administered 20 (±10)minutes after food had been offered by placement in the back of the oralcavity over the tongue to initiate swallowing.

Also on Day 0, commercially available Advocate® was administeredtopically to the other group of dogs (positive controls) according tothe product label. Due to the 28 days efficacy duration of Advocate®,these dogs were re-treated on Day 28 and 56. With the dog in a standingposition, the coat was parted until the skin was visible and theAdvocate® was administered directly onto the skin.

Both treated groups were observed prior to treatment and again hourlyfor four hours after treatment of the last animal, for possible adverseevents. Personnel performing the post-treatment observations wereblinded with respect to the treatment.

Mite Assessments

Deep skin scrapings (˜4 cm²) were made from five sites on each dog onDays −4, 28, 56 and 84 and were examined under a stereomicroscope forthe presence of Demodex spp. mites. Skin scrapings of the dogs treatedwith Advocate® were performed on Day 28 and Day 56, before the second orthird treatment was applied, respectively. The same sites and/or sitesof new lesions were scraped at each subsequent examination.

The clinical signs and the extent of demodectic lesions on each dog wereassessed on the days when skin scrapings were made, and recorded on astandardised form. The following parameters were assessed and sketchedon a silhouette (left and right hand side) for each dog: body areasexhibiting erythema; body areas covered by casts, scales and crusts;body areas with hair loss (1=slight thinning of hair; 2=conspicuous hairloss; 3=no hair). Colour photographs illustrating the extent of lesionsand their resolution, were taken of each dog on Day −4 and subsequentlyat approximately monthly intervals up to Day 84 after treatment. Asemi-quantitative assessment of hair re-growth was performed, comparinghair coat before and after the 12 weeks study duration.

Efficacy Evaluation

The primary assessment variable in the study was the decrease in numberof mites counted in skin scrapings (immature and adult live mitescombined) following treatment.

Efficacy was calculated using geometric means with Abbott's formula:

Efficacy(%)=(Mpre−Mpost)/Mpre×100

where Mpre was the mean number of pre-treatment mite counts, and Mpostthe mean number of post-treatment mite counts.

Additionally, the groups were compared using an ANOVA (Proc GLMprocedure in SAS) with a treatment effect after a logarithmictransformation on the mite (count+1) data.

One dog treated with Advocate® was removed from the study on Day 59 dueto malignant lymphoma. The results pertaining to this dog until Day 56,before its exclusion from the study on Day 59, have been included withthose of the other dogs in the group treated with Advocate®.

Results

No adverse event considered to be related to oral treatment withBravecto® chewable tablets or topical treatment with Advocate® wasobserved in any dog.

Treatment with Bravecto® chewable tablets resulted in a reduction in themean mite number present in skin scrapings of 99.8% on Day28, and of100% on Days 56 and 84 after treatment. The treatment with Advocate®resulted in a reduction in the mean mite number present in skinscrapings of 98.0% on Day 28, of 96.4% on Day 56, and of 94.7% on Day84. Statistically significantly (P 0.05) fewer mites were found on theBravecto® treated dogs compared to Advocate® treated dogs (Table 1).

TABLE 1 Geometric mean reductions in Demodex spp. mite counts of dogstreated once orally with Bravecto ® or topically on three occasions at28 day intervals with Advocate ® Study Days Study groups Bravecto ®Advocate ® p-value −4 Mean^(a) mite counts (n) 447.0 509.4/478.6 ^(b)Na^(c) Count range (n)  41-1740 79-2724 28 Mean^(a) mite counts (n)  0.810.0 Count range (n) 0-14 0-496 Efficacy (%)  99.8 98.0 0.0917 56Mean^(a) mite counts (n)  0.0 18.5 Count range (n) Na^(c) 0-115 Efficacy(%) 100.0 96.4 <0.0001 84 Mean^(a) mite counts (n)  0.0 25.6 Count range(n) Na^(c) 0-286 Efficacy (%) 100.0 94.7 0.0020 ^(a)Geometric mean ^(b)Mite counts calculated without one dog, which was euthanized on Day 59^(c)Not applicable

The prevalence of erythematous patches on the dogs treated once orallywith Bravecto® chewable tablets was reduced from 62.5% of the dogs onDay −4 prior to treatment to 12.5% of the dogs 12 weeks followinginitiation of treatment.

The prevalence of crusts, casts or scales was reduced from 100% prior totreatment to 12.5% 12 weeks following initiation of treatment.

In comparison, the prevalence of erythematous patches on dogs treatedthree times at a 28 days interval with Advocate® was reduced from 87.5%to 0% and the prevalence of crusts, casts and scales was reduced from100% to 42.9% (Table 2).

TABLE 2 Reduction in the prevalence of dermatologic changes in dogs withgeneralized demodicosis after treatment with either Bravecto ® orAdvocate ® Clinical Symptom Day −4 Day 28 Day 56 Day 84 Bravecto ®:prevalence of lesions on days before and after treatment^(a) (number ofdogs/number of dogs per group) Erythematous patches 62.5% (5/8) 37.5%(3/8) 12.5% (1/8) 12.5% (1/8) Crusts, casts or scales  100% (8/8) 62.5%(5/8) 62.5% (5/8) 12.5% (1/8) Advocate ®: prevalence of lesions on daysbefore and after initial treatment^(b) (number of dogs/number of dogsper group) Erythematous patches 87.5% (7/8)  50% (4/8)   0% (0/8)     0%(0/7)^(c) Crusts, casts or scales  100% (8/8)  100% (8/8) 37.5% (3/8) 42.9% (3/7)^(c) ^(a)Dogs were treated once orally on Day 0 ^(b)Dogswere treated topically on Day 0, on Day 28 and again on Day 56. Skinassessments were performed before treatment. ^(c)Mite counts calculatedwithout one dog, which was euthanized on Day 59.

Hair re-growth compared to the proportion of the body area covered byhair prior to treatment is summarized in Table 3. By Days 56 and 84after initiation of treatment, hair re-growth on the majority of dogs inboth groups exceeded the hair-coat of the dogs by 90% compared with thepre-treatment assessment.

TABLE 3 Hair re-growth on dogs with generalized demodectic mange aftertreatment with Bravecto ® or Advocate ® Hair re-growth score: frequencyof occurrence Bravecto ® ^(a) Advocate ® ^(b) (number of dogs/ (numberof dogs/ number of dogs per group) number of dogs per group) Study 1 2 31 2 3 day (0-50%) (50-90%) (>90%) (0-50%) (50-90%) (>90%) 28 3/8 1/8 4/86/8 1/8 1/8 56 0/8 1/8 7/8 0/8 1/8 7/8 84 0/8 1/8 7/8  0/7^(c)  1/7^(c) 6/7^(c) ^(a) Dogs were treated once orally on Day 0 ^(b) Dogs weretreated topically on Day 0, on Day 28 and again on Day 56. Skinassessments were performed before treatment. ^(c)Mite counts calculatedwithout one dog, which was euthanized on Day 59.

The body weight of every dog increased similarly in both groups duringthe study period.

CONCLUSIONS

Single oral administration of Bravecto® (13.64% fluralaner) chewabletablets is highly effective against generalized demodicosis, with nomites detectable at 56 and 84 days following treatment. In comparison,Advocate®(10% imidacloprid/2.5% moxidectin) administered three times at28 day intervals, is also highly effective against generalizeddemodicosis, but most dogs still harboured mites at all assessment timepoints. Both treatments resulted in a marked reduction of skin lesionsand increase of hair-growth 12 weeks after the initial treatment.

1. Method of treating generalized demodicosis in mammals comprisingadministering an effective amount of an isoxazoline compound of formula(I)

wherein R¹=halogen, CF₃, OCF₃, CN, n=integer from 0 to 3,R²=C₁-C₃-haloalkyl, T=5- or 6-membered ring, which is optionallysubstituted by one or more radicals Y, Y=methyl, halomethyl, halogen,CN, NO₂, NH₂—C═S, or two adjacent radicals Y form together a chain,Q=X—NR³R⁴ or a 5-membered N-heteroaryl ring, which is optionallysubstituted by one or more radicals; X=CH₂, CH(CH₃), CH(CN), CO, CS,R³=hydrogen, methyl, haloethyl, halopropyl, halobutyl, methoxymethyl,methoxyethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl,propoxymethyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl,dimethoxyethyl, propynylaminocarbonylmethyl, N-phenyl-N-methyl-amino,haloethylaminocarbonylmethyl, haloethylaminocarbonylethyl,tetrahydrofuryl, methylaminocarbonylmethyl,(N,N-dimethylamino)-carbonylmethyl, propylaminocarbonylmethyl,cyclopropylaminocarbonylmethyl, propenylaminocarbonylmethyl,haloethylaminocarbonylcyclopropyl,

wherein Z^(A)=hydrogen, halogen, cyano, halomethyl (CF₃); R⁴=hydrogen,ethyl, methoxymethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl,propoxymethyl, methylcarbonyl, ethylcarbonyl, propylcarbonyl,cyclopropylcarbonyl, methoxycarbonyl, methoxymethylcarbonyl,aminocarbonyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl,dimethoxyethyl, propynylaminocarbonylmethyl,haloethylaminocarbonylmethyl, cyanomethylaminocarbonylmethyl, orhaloethylaminocarbonylethyl; or R³ and R⁴ together form a substituentselected from the group consisting of:

or a salt or solvate or N oxide thereof.
 2. The method according toclaim 1 wherein the isoxazoline compound of formula (I) is fluralaner.3. The method according to claim 1 wherein the isoxazoline compound isadministered once, twice or three times.
 4. The method according toclaim 1 comprising a single administration of the isoxazoline compoundto a mammal.
 5. The method according to claim 1 wherein the isoxazolinecompound is administered to the mammal orally
 6. The method according toclaim 1 to wherein the isoxazoline compound is administered to themammal topically.
 7. The method according to claim 1 wherein theisoxazoline compound is administered to the mammal parenterally byinjection.
 8. The method according to claim 1 wherein the mammal is acompanion animal.
 9. The method according to claim 1 wherein thecompanion animal is a dog.
 10. (canceled)
 11. (canceled)
 12. (canceled)13. (canceled)
 14. (canceled)
 15. (canceled)
 16. The method according toclaim 1 wherein the isoxazoline compound is afoxalaner.
 17. The methodaccording to claim 1 wherein the isoxazoline compound is sarolaner. 18.The method according to claim 1 comprising a single administration of10-40 mg/kg bodyweight fluralaner to dogs that have been diagnosed withgeneralized demodicosis.
 19. The method of claim 1, where n is 1, 2 or3.
 20. The method of claim 1, wherein R² is CF₃ or CF₂Cl.
 21. The methodof claim 1, wherein two adjacent radicals Y form together a three orfour membered chain.